On 2022-04-12 20:28, Ludovic Courtès wrote:
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> Hi,
>
> Andrew Tropin <andrew@trop.in> skribis:
>
>> Prepared a patch series, which fixes the issues and sligthly adjusts the
>> way home shepherd reload configuration logic works, now it happens only
>> if configuration is changed and also it doesn't try to be smart and
>> start a shepherd if it's not started yet.
>>
>> From d2578f8924217451ca20f0b61fd6f9b9d31c930d Mon Sep 17 00:00:00 2001
>> From: Andrew Tropin <andrew@trop.in>
>> Date: Tue, 12 Apr 2022 11:30:58 +0300
>> Subject: [PATCH 1/3] home: shepherd: Prevent launching the second instance.
>>
>> * gnu/home/services/shepherd.scm: Prevent launching the second instance.
>
> I applied this one with a convention commit log, including a “Fixes”
> line, which is important for traceability. (Please check the ChangeLog
> convention for future patches.)
>
Read it from time to time, but the information about contribution
guidelines is too much spreaded, for example I can't find info about
Fixes line even with search, but maybe I just not very attentive.
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>> From 56d16b4cd511f6837329b888dade0c6d6da4d89d Mon Sep 17 00:00:00 2001
>> From: Andrew Tropin <andrew@trop.in>
>> Date: Tue, 12 Apr 2022 12:19:50 +0300
>> Subject: [PATCH 2/3] home: shepherd: Use run-on-change to reload shepherd
>> config.
>>
>> * gnu/home/services/shepherd.scm: Add shepherd configuration to
>> XDG_CONFIG_HOME and use it instead of full path to the store. It's necessary
>> to use run-on-change service.
>
> [...]
>
>> +++ b/gnu/home/services/shepherd.scm
>> @@ -105,27 +105,30 @@ (define (launch-shepherd-gexp config)
>> (system*
>> #$(file-append shepherd "/bin/shepherd")
>> "--logfile"
>> - (string-append log-dir "/shepherd.log")
>> - "--config"
>> - #$(home-shepherd-configuration-file services shepherd)))))
>> + (string-append log-dir "/shepherd.log")))))
>> #~"")))
>>
>> (define (reload-configuration-gexp config)
>> (let* ((shepherd (home-shepherd-configuration-shepherd config))
>> (services (home-shepherd-configuration-services config)))
>> - #~(system*
>> - #$(file-append shepherd "/bin/herd")
>> - "load" "root"
>> - #$(home-shepherd-configuration-file services shepherd))))
>> + #~(when (file-exists?
>> + (string-append
>> + (or (getenv "XDG_RUNTIME_DIR")
>> + (format #f "/run/user/~a" (getuid)))
>> + "/shepherd/socket"))
>> + (system*
>> + #$(file-append shepherd "/bin/herd")
>> + "load" "root"
>> + #$(home-shepherd-configuration-file services shepherd)))))
>>
>> -(define (ensure-shepherd-gexp config)
>> - #~(if (file-exists?
>> - (string-append
>> - (or (getenv "XDG_RUNTIME_DIR")
>> - (format #f "/run/user/~a" (getuid)))
>> - "/shepherd/socket"))
>> - #$(reload-configuration-gexp config)
>> - #$(launch-shepherd-gexp config)))
>> +(define (add-shepherd-configuration config)
>> + (let* ((shepherd (home-shepherd-configuration-shepherd config))
>> + (services (home-shepherd-configuration-services config)))
>> + `(("shepherd/init.scm"
>> + ,(home-shepherd-configuration-file services shepherd)))))
>> +
>> +(define (home-shepherd-run-on-change config)
>> + `(("files/.config/shepherd/init.scm" ,(reload-configuration-gexp config))))
>
> How does this relate to the bug at hand?
>
> https://issues.guix.gnu.org/54545
>
Almost directly.
During activation if there is no shepherd process we tried to launch a
new one, which was useful back in the days, when I was testing changes
frequently, but can be kinda unexpected for user, if they stopped
Shepherd for some reason, but during activation it started again
automatically. As we discussed earlier:
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>>> Probably we need to do config reload using on-change service and also
>>> not trigger on-change stuff if user isn't logged in.
>> Makes sense.
it would be nice to reload configuration only if it's changed. To make
run-on-change work we need to store a config somewhere in
home-environment, to make it possible to compare with previous
generation. files/.config/shepherd/init.scm looks like a good match
here, in addition to on-change functionality it increases explorability.
Toggle quote (4 lines)
> As discussed elsewhere, I find it less ambiguous to pass store file
> names for configuration files.
>
I don't know how much value in it, but we can keep those lines:
Toggle quote (10 lines)
>> - "--config"
>> - #$(home-shepherd-configuration-file services shepherd)))))
>
> That can be a drawback in some cases, for daemons that won’t be able
> to load a new config from a different location, but shepherd is not in
> that category: it can load a config file via ‘herd load root’ from any
> place.
>
It is how reload gexp works.
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> Last, it would be nice if we could use the (guix scripts system
> reconfigure) machinery like ‘guix system reconfigure’ and ‘guix deploy’
> to upgrade services. An idea for future work. :-)
>
>> From e80e9fae6f6bcd478fa904aad8eb426da3f42f10 Mon Sep 17 00:00:00 2001
>> From: Andrew Tropin <andrew@trop.in>
>> Date: Tue, 12 Apr 2022 12:23:26 +0300
>> Subject: [PATCH 3/3] home: run-on-first-login: Add a startup message to the
>> script.
>>
>> gnu/home/services.scm: Add a startup message to the script to make it clear
>> when it begins.
>> ---
>> gnu/home/services.scm | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/gnu/home/services.scm b/gnu/home/services.scm
>> index 49bd6e3555..e2c51910a8 100644
>> --- a/gnu/home/services.scm
>> +++ b/gnu/home/services.scm
>> @@ -344,6 +344,7 @@ (define (compute-on-first-login-script _ gexps)
>> #~(begin
>> (use-modules (guix i18n))
>> #$%initialize-gettext
>> + (display (G_ "Starting run-on-first-login script.\n\n"))
>
> I’m not fond of unconditional low-level logging. In Guix there’s
> relatively little logging and whatever logging there is is controlled by
> ‘-v’; I think we should follow that approach as much as possible.
>
> Thank you!
>
> Ludo’.
--
Best regards,
Andrew Tropin
